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Bulletin American Museum of Natural History. [Vol. XXXVII, 



orbital breadth, 4; breadth at base of canines, 5.6; length of upper toothrow (with 

 canine), 6.7; length of mandible, 12.2; angle to condyle, 3.6; depth at coronoid, 

 3.1; length of lower toothrow, 7.4. 



Skulls of type and 16 topotypes, total length, 18.8 (18.2-19.4) ; zygomatic breadth, 

 12 (11.4-12.5). 



Braincase low and flat, sagittal and lambdoid crests slightly developed, the latter 

 indicated only in old adults; prebrbital process absent or barely indicated. Pre- 

 maxillse emarginate behind base of incisors. Upper incisors small, slightly con- 

 vergent apically, widely separated from each other and the canines. First upper 

 premolar very small, in midline of toothrow and not crowded between the adjoining 

 teeth. Lower incisors 2-2, small, crowded in a convex row between canines. First 

 lower premolar about half the size of the second. Coronoid process small and low, 

 barely reaching the level of the condyles, and directed outward. 



This striking species is represented by 22 specimens, 18 skins with skulls 

 and 4 in alcohol, all taken the same day at Medje, and all adult. Only 4 

 are males, and of the 14 female skins 1 1 are labeled as " carrying an embryo 

 in right uterus." One of the alcoholic specimens is in poor condition, the 

 ears and membranes being abraded and light colored, and the orange of the 

 underparts is faded to pale yellow. This specimen was taken at first to 

 represent a different but (owing to its condition) an unidentifiable species, 

 and was so listed in this paper, but Mr. Lang assures me that this is one of 

 the 22 specimens of N. ochraceus taken at Medje, all on the same day, and 

 that its present abraded and bleached condition is due to bad preservation 

 due to an accident in transportation. 



Nyctinomus ochraceus appears to be related to N. thersites Thornas but 

 it is smaller (forearm 38, in thersites 41; skull 18.8 X 12; in thersites 20 X 

 12.5), and the lower premolars are not subequal as in thersites. N. thersites 

 is described as " colour dark brownish chestnut, the glandular hairs behind 

 the junction of the ears black." This applies fairly well to the upperparts 

 of N. ochraceus, except that the lengthened hairs behind the ears in males are 

 not black but dark chestnut. It is hardly possible, however, that this brief 

 description could apply if the lower parts had been ochraceous-orange? as 

 in the species here described. 



55. Chaerephon frater sp. nov. 



Type, No. 49275, 9 ad. (alcoholic), Malela (near Boma), southwestern Belgian 

 Congo, July 8, 1915; Herbert Lang and James P. Chapin. American Museum Congo 

 Expedition. Orig. No. 2613. 



Similar to Chcerephon hindei in general coloration but smaller, skull less massive 

 and the dentition weaker, with p 2 much smaller. 



Coloration, including the wing membranes, practically the same as in C. hindei, 

 so far as can be determined from alcoholic material, except that the proximal border 



